The present invention relates to gratings and more particularly to an improved grating with bars attached at intersections by crimping.
Gratings (also called grilles, lattices, louvers, etc), of many types are used for many purposes. A typical grating includes a number of main bars or bearing bars extending generally parallel in a first direction, with cross bars or support bars extending in a transverse direction. The bars are attached at the intersections to form a single structure. For load bearing applications, the main and/or cross bars are relatively strong and are structurally supported. Examples of load bearing gratings are those used for floors or convector grilles in floors. Gratings can also be used as decorative grilles where high strength is not required.
One well known type of grating is made by welding the main bars and cross bars together at the intersections. A problem with this approach is that expensive equipment or a large amount of labor is required to make the numerous welds required for a grating. Another problem is that welds can be messy, requiring post assembly cleaning and trimming of weld splatter and smoke discoloration. A further disadvantage is that welding may not be practical when the main and cross bars are of dissimilar materials.
In order to overcome disadvantages of welding, gratings are made using a tight tolerance press fit. Slots in the main and cross bars are mated at the intersections with a very large force and the resulting interference fit mechanically holds the assembly together. The equipment needed to make this type of grating is specialized and very expensive. In addition, the close tolerances needed for the bar structures adds to the cost.
Other gratings are made with fasteners. For example, rivets can be used to attach crimp bars to main bars to make a strong load bearing grating. This type of grating is expensive and time consuming to make due to the riveting process in addition, for many architectural applications, a riveted grating is not as attractive as a grating having a simple, clean, geometrical pattern of crossing bars.
Objects of the present invention are to provide an improved grating that can be made with a minimum of labor and machinery expense; to provide a grating that has an attractive, neat appearance without requiring any post assembly cleaning; to provide a grating that can be made of bars of a wide variety of different materials sizes and shapes; to provide a grating that has ample strength for load bearing applications and that has an attractive appearance for decorative applications; and to provide a grating overcoming disadvantages of gratings known in the past.
In brief, in accordance with the invention there is provided a grating including a plurality of first bars and a plurality of second bars and a plurality of intersections of the first and second bars. The first and second bars include edges and slots in the edges. Each first bar includes deformable arms adjacent the slots in the first bar. Each second bar includes recesses adjacent the slots in the second bar. Each intersection includes aligned and interfitted slots of the first and second bars. The slot of the first bar receives the second bar and the slot of the second bar receives the first bar. A deformable arm of the first bar is crimped to extend in locking engagement into a recess of the second bar.